python - 如何修补对象中的属性

Question

问题是如何在 with 语句中修补实例的属性。我尝试了以下不起作用的示例。它像评论中一样打印。

from mock import patch, PropertyMock

class Foo(object):
    f = {'a': 1}

new_foo = Foo()

with patch.object(new_foo, 'f', new_callable=PropertyMock) as mock:
    mock.return_value = {'b': 2}
    print new_foo.f
    # <PropertyMock name='f' id='4474801232'>

Answer 1

documentation 中有一个示例.您需要将类提供给 patch.object，而不是实例化对象。

from mock import patch, PropertyMock

class Foo(object):
    f = {'a': 1}

new_foo = Foo()

with patch.object(Foo, 'f', new_callable=PropertyMock) as mock:
    mock.return_value = {'b': 2}
    print new_foo.f

print new_foo.f

输出:

{'b': 2}
{'a': 1}